challenge

A challenge is defined as a demand for proof or an invitation to participate in a competition.

(noun)

An example of challenge is a guard asking for identification.
An example of challenge is a boxer asking another boxer to take part in a boxing match.

The definition of a challenge is an act of rebellion against someone or something.

(noun)

An example of challenge is an employee questioning the actions of their supervisor in a meeting.

Challenge means to stop someone and ask for their identification.

(verb)

An example of challenge is someone being stopped at a border crossing to show their passport.

See challenge in Webster's New World College Dictionary

noun

a demand for identification: a sentry gave the challenge
a calling into question; a demanding of proof, explanation, etc.: a challenge of the premises of an argument
a call or dare to take part in a duel, contest, etc.
anything, as a demanding task, that calls for special effort or dedication
☆ an objection to a vote or to someone's right to vote
Law a formal objection or exception to a person who has been chosen as a prospective juror

Origin: ME & OFr chalenge, accusation, claim, dispute < L calumnia, calumny

to call to a halt for identification
1. to call to account
2. to make objection to; call into question
to call or dare to take part in a duel, contest, etc.; defy
to call for; make demands on: to challenge the imagination
☆ to object to (a vote) as not valid or (a prospective voter) as not qualified to vote
to take formal exception to (a prospective juror)

intransitive verb

to make, issue, or offer a challenge

Related Forms:

See challenge in American Heritage Dictionary 4

noun

a. A call to engage in a contest, fight, or competition: a challenge to a duel.
b. An act or statement of defiance; a call to confrontation: a challenge to the government's authority.
A demand for explanation or justification; a calling into question: a challenge to a theory.
A sentry's call to an unknown party for proper identification.
A test of one's abilities or resources in a demanding but stimulating undertaking: a career that offers a challenge.
A claim that a vote is invalid or that a voter is unqualified.
Law A formal objection to the inclusion of a prospective juror in a jury.
Immunology The induction or evaluation of an immune response in an organism by administration of a specific antigen to which it has been sensitized.

verb chal·lenged, chal·leng·ing, chal·leng·es

verb, transitive

a. To call to engage in a contest, fight, or competition: challenged me to a game of chess.
b. To invite with defiance; dare: challenged him to contradict her. See Synonyms at defy.
To take exception to; call into question; dispute: a book that challenges established beliefs.
To order to halt and be identified, as by a sentry.
Law To take formal objection to (a prospective juror).
To question the qualifications of (a voter) or validity of (a vote).
To have due claim to; call for: events that challenge our attention.
To summon to action, effort, or use; stimulate: a problem that challenges the imagination.
Immunology To induce or evaluate an immune response in (an organism) by administering a specific antigen to which it has been sensitized.